Ok. I got the to Portainer deployment step and got this error:
Deployment error
failed to deploy a stack: Creating network "nextcloud_default" with the default driver Pulling mariadb (ghcr.io/linuxserver/mariadb:)... Get "https://ghcr.io/v2/": dial tcp: lookup ghcr.io on [::1]:53: read udp [::1]:33850->[::1]:53: read: connection refused : exit status 1